MyD88-dependent protective immunity elicited by adenovirus 5 expressing the surface antigen 1 fromToxoplasma gondiiis mediated by CD8+T lymphocytes

• Published in: Vaccine Vol. 29; no. 27; p. 4476
• Main Authors: Mendes, Érica A, Caetano, Bráulia C, Penido, Marcus LO, Bruna-Romero, Oscar, Gazzinelli, Ricardo T
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Limited 15.06.2011
• Subjects: Animals; Cysts; Immune system; Immunology; Infections; Lymphocytes; Mortality; Parasites; Protozoa; Studies; Vaccines
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2011.04.044

Toxoplasma gondiiis an intracellular parasite widely spread around the world. The surface antigens (SAG) 1, 2 and 3 are the main proteins expressed on the surface ofT. gondiitachyzoites. Replication-defective adenovirus serotype 5 (rAd5) is one of the most potent recombinant viral vectors for eliciting T cell-mediated immunity in mice and humans. Here we show that vaccination with rAd5 expressing SAG1 (AdSAG1), but neither SAG2 nor SAG3, induces protective immunity in the highly susceptible C57BL/6 mice challenged withT. gondii. Furthermore, we evaluated different immunological components involved on viral induced protective immunity. We observed that host protection elicited by AdSAG1 is highly dependent on IL-12, IFN-γ and CD8+T lymphocytes. Importantly, the induction of protective immunity (T cell-derived IFN-γ) was also dependent on Myeloid Differentiation Factor 88 (MyD88), and thus, likely to involve Toll-like Receptors. We conclude that protective parasite specific-CD8+T cells are elicited by a mechanism that involves MyD88-dependent induction of IL-12.